Default DNS setup in ISPconfig 3

Now I'm testing ISPconfig 3, and would like to set the default DNS.
Where can I find this option?
Is this in System > Server > Nameservers, and if so should I add it like ns1.domain.tld, ns2.domain.tld (separated with commas?)

ISPConfig 3 has no default setting for nameservers. The field in the server settings are the nameservers that your server uses to resolve domains (the servers listed in /etc/resolv.conf) and not the nameservers that you uses for your own domains.